Subject: bug#26816: mouse movement support for OS X

From: "Charles A. Roelli" <[email-masked]>
Date: Sun, 14 May 2017 15:29:57 +0200

Attached is a patch now working with multiple monitors.  I also added 
`ns-set-mouse-absolute-pixel-position', a test and a NEWS entry.  The 
test works interactively, but it requires a frame to run and I'm not 
sure whether tests run with them by default.

The code for handling the y-coord in 
`ns-set-mouse-absolute-pixel-position' is from 
`ns-display-monitor-attributes-list' (in the calculation of the screen 
geometry).  I also made (set-mouse-absolute-pixel-position 0 0) put the 
mouse in the top-left corner of the current screen.

I tried out both `set-mouse-position' and 
`set-mouse-absolute-pixel-position' on setups with the secondary monitor 
on the left, right, top and bottom, and they seem to work right.

I also got rid of the call to `ns_raise_frame' in 
`frame_set_mouse_pixel_position', which is unnecessary.

>> This now reminds me of a related problem, though: with Emacs 25.2 (or in
>> Emacs 26, with the above change applied to NS_PARENT_WINDOW_TOP_POS(f)),
>> tooltips originating from an area with a help-echo property (like "Lisp
>> Interaction" in the mode line in emacs -Q) in a frame on the secondary
>> monitor actually show up in the primary monitor instead -- as if the tooltip
>> frame is constrained to having a positive x-coordinate only.  I haven't
>> found where it happens, but I guess the cause is similar.
> Look at compute_tip_xy in nsfns.m. It moves tooltips into the positive
> screen space. I’ve not managed to get to grips with this code yet.
>
> I think what we want is for it to try to keep the tooltip on one
> screen, so it’s not spanning two monitors, but allow it to go into
> negative space.
>
> Perhaps this should be a separate bug report.

Done (#26905).
diff --git a/etc/NEWS b/etc/NEWS
index 6667a44..25f0f18 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1292,6 +1292,9 @@ This is in contrast to the default action on POSIX Systems, where it
 causes the receiving process to terminate with a core dump if no
 debugger has been attached to it.
 
+** `set-mouse-position' and `set-mouse-absolute-pixel-position' work
+on macOS.
+
 
 ----------------------------------------------------------------------
 This file is part of GNU Emacs.
diff --git a/lisp/frame.el b/lisp/frame.el
index 05db8cf..02871e0 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -1465,6 +1465,7 @@ mouse-absolute-pixel-position
      (t
       (cons 0 0)))))
 
+(declare-function ns-set-mouse-absolute-pixel-position "nsfns.m" (x y))
 (declare-function w32-set-mouse-absolute-pixel-position "w32fns.c" (x y))
 (declare-function x-set-mouse-absolute-pixel-position "xfns.c" (x y))
 
@@ -1474,6 +1475,8 @@ set-mouse-absolute-pixel-position
 position (0, 0) of the selected frame's terminal."
   (let ((frame-type (framep-on-display)))
     (cond
+     ((eq frame-type 'ns)
+      (ns-set-mouse-absolute-pixel-position x y))
      ((eq frame-type 'x)
       (x-set-mouse-absolute-pixel-position x y))
      ((eq frame-type 'w32)
diff --git a/src/nsfns.m b/src/nsfns.m
index cbe0ffb..e916f6a 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -3053,6 +3053,44 @@ value is a list of the form (LEFT, TOP, RIGHT, BOTTOM).  All values are
 				 : Qnative_edges));
 }
 
+DEFUN ("ns-set-mouse-absolute-pixel-position",
+       Fns_set_mouse_absolute_pixel_position,
+       Sns_set_mouse_absolute_pixel_position, 2, 2, 0,
+       doc: /* Move mouse pointer to absolute pixel position (X, Y).
+The coordinates X and Y are interpreted in pixels relative to a position
+\(0, 0) of the selected frame's display.  */)
+       (Lisp_Object x, Lisp_Object y)
+{
+  struct frame *f = SELECTED_FRAME ();
+  EmacsView *view = FRAME_NS_VIEW (f);
+  NSScreen *screen = [[view window] screen];
+  NSRect screen_frame = [screen frame];
+  int mouse_x, mouse_y;
+
+  NSScreen *primary_screen = [[NSScreen screens] objectAtIndex:0];
+  NSRect primary_screen_frame = [primary_screen frame];
+  CGFloat primary_screen_height = primary_screen_frame.size.height;
+
+  if (FRAME_INITIAL_P (f) || !FRAME_NS_P (f))
+    return Qnil;
+
+  CHECK_TYPE_RANGED_INTEGER (int, x);
+  CHECK_TYPE_RANGED_INTEGER (int, y);
+
+  mouse_x = screen_frame.origin.x + XINT (x);
+
+  if (screen == primary_screen)
+    mouse_y = screen_frame.origin.y + XINT (y);
+  else
+    mouse_y = (primary_screen_height - screen_frame.size.height
+	       - screen_frame.origin.y) + XINT (y);
+
+  CGPoint mouse_pos = CGPointMake(mouse_x, mouse_y);
+  CGWarpMouseCursorPosition (mouse_pos);
+
+  return Qnil;
+}
+
 /* ==========================================================================
 
     Class implementations
@@ -3241,6 +3279,7 @@ - (NSString *)panel: (id)sender userEnteredFilename: (NSString *)filename
   defsubr (&Sns_frame_edges);
   defsubr (&Sns_frame_list_z_order);
   defsubr (&Sns_frame_restack);
+  defsubr (&Sns_set_mouse_absolute_pixel_position);
   defsubr (&Sx_display_mm_width);
   defsubr (&Sx_display_mm_height);
   defsubr (&Sx_display_screens);
diff --git a/src/nsterm.h b/src/nsterm.h
index 9285178..ac339bf 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -1087,7 +1087,7 @@ struct x_output
    ? ([[FRAME_NS_VIEW (f) window] parentWindow].frame.origin.y          \
       + [[FRAME_NS_VIEW (f) window] parentWindow].frame.size.height     \
       - FRAME_NS_TITLEBAR_HEIGHT (FRAME_PARENT_FRAME (f)))              \
-   : [[[FRAME_NS_VIEW (f) window] screen] frame].size.height)
+   : [[[NSScreen screens] objectAtIndex: 0] frame].size.height)
 
 #define FRAME_NS_FONT_TABLE(f) (FRAME_DISPLAY_INFO (f)->font_table)
 
diff --git a/src/nsterm.m b/src/nsterm.m
index c22c5a7..a7ab73b 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -2321,14 +2321,14 @@ so some key presses (TAB) are swallowed by the system. */
    -------------------------------------------------------------------------- */
 {
   NSTRACE ("frame_set_mouse_pixel_position");
-  ns_raise_frame (f);
-#if 0
-  /* FIXME: this does not work, and what about GNUstep? */
+
+  /* FIXME: what about GNUstep? */
 #ifdef NS_IMPL_COCOA
-  [FRAME_NS_VIEW (f) lockFocus];
-  PSsetmouse ((float)pix_x, (float)pix_y);
-  [FRAME_NS_VIEW (f) unlockFocus];
-#endif
+  CGPoint mouse_pos =
+    CGPointMake(f->left_pos + pix_x,
+                f->top_pos + pix_y +
+                FRAME_NS_TITLEBAR_HEIGHT(f) + FRAME_TOOLBAR_HEIGHT(f));
+  CGWarpMouseCursorPosition (mouse_pos);
 #endif
 }
 
diff --git a/test/lisp/mouse-tests.el b/test/lisp/mouse-tests.el
index fffaa2f..c743df4 100644
--- a/test/lisp/mouse-tests.el
+++ b/test/lisp/mouse-tests.el
@@ -47,4 +47,12 @@
     (should-not (mouse--down-1-maybe-follows-link))
     (should (equal unread-command-events '((mouse-2 nil 1))))))
 
+(ert-deftest bug26816-mouse-frame-movement ()
+  "Mouse moves relative to frame."
+  (let ((frame (selected-frame)))
+    (set-mouse-position frame 0 0)
+    (should (equal (mouse-position)
+		   (cons frame (cons 0 0))))))
+
+
 ;;; mouse-tests.el ends here